1(a). group 1 and group 7 of the periodic table both

1(a). Group 1 and Group 7 of the Periodic Table both contain reactive elements.

Sodium, Na, reacts with water, H2O.

Write a balanced symbol equation for this reaction.

[2] (b). Complete the table below to show the molecular formula, state and colour of the three Group 7 elements.

Chlorine Bromine Iodine

Molecular formula

State (at roomtemperature)

Colour

[3]

© OCR 2019. 1 of 45 PhysicsAndMathsTutor.com

2(a). Mendeleev organised the elements into the first Periodic Table.The diagram shows some elements from Mendeleev's groups 2 and 3.

Mendeleev left gaps in his table.

Two gaps are shown in Group 3.

Explain why these gaps were so important.

[2]

(b). Two of the elements in Mendeleev's Group 2 are not in Group 2 of the modern Periodic Table.

Identify the elements and state where they are found in the modern Periodic Table.

[2]


3(a). Silver chloride is a salt that is used to make lenses that darken in bright light.

Silver chloride can be made from silver nitrate in a precipitation reaction.

This is the symbol equation for the reaction.

(i) Explain how this equation shows that silver chloride forms as a precipitate.

[1]

(ii) Write a word equation for the reaction.

[1]

(b). When light shines on silver chloride, AgCl, a solid forms which makes the lenses go dark.

The solid is silver metal.

Suggest the name of the other element that forms in the reaction.

[1]


4(a). The table gives some information about the elements in Group 7.

Complete the table by filling in the missing information.

Element Normal state at room temperature Colour at room temperature

fluorine gas pale yellow

chlorine

bromine

iodine grey

[2] (b). Which statements about the atoms of the elements in Group 7 are true?

Put ticks (?) in the boxes next to the two correct answers. They all have the same number of electron shells.

They all have the same number of outer shell electrons.

They all form ions with the same charge.

They all have the same charge on the nucleus.

They all form ions by losing electrons.

[2] (c). Group 7 elements are diatomic.

What does this mean?

[2]


5(a). Sodium and potassium are elements in Group 1 of the Periodic Table.

Jake watches a video of the reaction between sodium and water.

Complete the word equation for the reaction between sodium and water.

[2] (b). Jake thinks that the reaction makes an alkali.

How could you show that a solution has an alkaline pH?

[2]


(c). Jake watches another video. This video shows the reaction of potassium with water.

How is this reaction different from the reaction of sodium with water?

Put ticks (✔) in the boxes next to the two correct answers.

The two reactions make different gases.

The reaction of sodium takes less time than the reaction of potassium.

The reaction with potassium makes an acid.

The two reactions have different rates.

The two reactions make different alkalis.

[1]


6(a). Hydrogen reacts with the elements in Group 7 of the Periodic Table.

Hydrogen and fluorine explode when they are mixed together.

The word equation for the reaction is

The formula for hydrogen fluoride is HF.

Write a balanced symbol equation for the reaction between hydrogen and fluorine.

[2]

(b). Iodine is another element in Group 7.

Predict the name and the formula of the compound that is made when iodine reacts with hydrogen.

name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

formula _ _ _ _ _ _ _ _ _ _ _ _ _ _

[2]


(c). The table shows what happens when fluorine, chlorine and iodine react with hydrogen.

Element Reaction when mixed with hydrogen

fluorine explodes at room temperature

chlorine a small spark is enough to make the mixture explode

iodine reacts slowly when heated strongly

(i) Describe the trend in reactivity of the Group 7 elements with hydrogen.

[1]

(ii) Bromine reacts steadily with hydrogen when it is heated. Does this fit the trend of reactivity of the other halogens? Explain your reasoning.

[2]


7. The table shows some information about the element hydrogen.

Properties of hydrogen

State at room temperature gas

Type of element non-metal

Atomic number 1

Number of electrons in outer shell of an atom 1

Maximum number of electrons the outer shell can hold 2

Ion H +

Formula of chloride HCl

Reactivity Very flammable.Reacts with both metals and non-metals.Does not react with water.

Fay and Guy are discussing where hydrogen fits in the Periodic Table.

Use information in the table and your knowledge of Group 1 elements to evaluate the ideas of Fay and Guy.

The quality of written communication will be assessed in your answer.


[6]


8(a). Jack writes down data about some elements in Group 7.

Element Formula ofmolecule

Normal physical state (roomtemperature 20 °C)

Melting point in °C Boiling point in °C

fluorine F2 gas ?220 ?188

chlorine Cl2 gas ?101 ?35

bromine Br2 liquid ?7 ?59

iodine I2 solid 114 184

Jack has made a mistake. One of the boiling points is wrong.

Which boiling point in the table is wrong?

Explain how you made your choice.

[2]

(b). Estimate the correct value for the boiling point.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ °C [1] (c). Astatine is another element in Group 7 of the Periodic Table.

What is the formula for a molecule of astatine?

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ [1]


9(a). Mendeleev developed the modern Periodic Table. Other scientists were involved.

Which two scientists are doing a peer review?

Explain how what they say is peer review.


[3]

(b). Mendeleev's ideas were supported by the discoveries of Scientist 3 and Scientist 4.

Explain why.

[2]


10(a).

Abbi does some experiments with Group 7 elements.

Abbi does an experiment using chlorine.

She uses a fume cupboard.

Explain why chlorine is hazardous.

[2]


(b). Abbi passes bromine vapour over a filter paper soaked in potassium iodide solution. Bromine vapour is blownonto the filter paper down a tube.

A grey solid appears on the filter paper because iodine is made.

Complete the symbol equation for this reaction.

[2]


(c). Abbi repeats the experiment using chlorine gas.

She passes chlorine gas down a tube onto filter papers soaked in some other Group 7 compounds.

The table shows which compounds she uses.

Gas Group 7 compound on filterpaper

chlorine potassium fluoride

chlorine potassium chloride

chlorine potassium bromide

chlorine potassium iodide

Before the experiment the solutions of the compounds are all colourless.

State and explain what Abbi will see when chlorine gas passes over each Group 7 compound.


[6]


11(a).

Jack investigates the reactions of some Group 1 and Group 2 metals with water.

He adds a small piece of each metal to water and measures how long it takes for the reaction to finish.

He uses the same amount of metal and the same amount of water each time.

The table shows his results.

Metal Group Time taken for reaction to finish in s

lithium 1 35

sodium 1 12

potassium 1 5

magnesium 2 not finished after 2 minutes

calcium 2 40

strontium 2 9

What conclusions can you make from the data about the reactivity of Group 1 and Group 2 metals with water?

[3]

(b). Which of the following statements about the reactions of the Group 1 metals with water are true and which are false?

Put a tick (?) in one box in each row.

True False

The reactions make hydrogen gas.

Each reaction makes a different metal oxide.

The reaction mixture gains mass during every reaction.

The pH of each solution is neutral at the end of the reaction.

[2]


12. Joe does some research about atoms of Group 1 elements.

He finds data about the radius of each atom.

He also finds data about the energy needed to remove one electron from the outer shell (energy level) of eachatom.

Element name Total number of electronsin each atom

Radius of the atom in pm Energy needed to removeone outer shell electron in

arbitrary units

lithium 3 152 520

sodium 11 186 490

potassium 19 231 420

Joe works out the number of electron shells in each atom and puts forward a hypothesis.

What trends does the table show? How does the number of electron shells in each atom link to these trends?

You may use diagrams to show the electron shells in each atom to support your answer.



[6]

13(a).

Ling carries out an investigation of the halogens.

Ling reacts some chlorine solution with a solution of potassium bromide.

The solution turns brown.

Explain why.

Include an ionic equation in your answer.

[3]


(b). Ling sees that the element astatine, At, is below iodine in Group 7.

She makes some predictions about astatine.

Which predictions about astatine are correct?

Tick (✓) two boxes.

Astatine is white.

Astatine is a gas.

Astatine reacts with sodium to form NaAt.

Astatine is less reactive than iodine.

[1]


14(a).

The diagram shows the arrangement of electrons in an atom of an element, element X.

Use the diagram and the Periodic Table to identify the element and to complete the missing information in thetable.

Name of element Number of electrons 9 Number of protons Number of neutrons Periodic Table Group

[3]


(b). The diagram below shows the arrangement of electrons in an ion of another element from the same group, element Y.

(i) What is the charge on the ion?

Explain your answer.

Charge

Explanation

[2]

(ii) Explain how you can tell from the diagrams that element X and element Y are in the same group of thePeriodic Table.

[1]


15(a).

About 150 years ago, Dimitri Mendeleev developed an early version of the Periodic Table. His Periodic Table had eight groups. He put elements with similar properties into the same group.

The table shows some of the elements that Mendeleev grouped together.

Mendeleev’s groups

1 2 3 4 5 6 7 8

LiNaK

Cu

BeMgZn

BAl

CSi

NP

OSCr

FClBr

FeCoNi

Some of Mendeleev’s groups contain similar elements to groups in the modern Periodic Table.

Which group in Mendeleev’s table contains the elements now found in Group 14 of the modern Periodic Table?

Group

[1]

(b). None of the elements from Group 18 of the modern Periodic Table are shown on Mendeleev’s table.

Suggest a reason why.

[1]


(c). Mendeleev put some of the transition metals into his Group 8.

He put some other transition metals into the other groups.

Give the symbols for three transition metals in Mendeleev’s table that he did not put in Group 8.

1

2

3

[2]

END OF QUESTION PAPER


1 a 2Na + 2H2O ⟶ 2NaOH + H2 ✔✔ 2 One mark for correct symbolsOne mark for balancing

b 3 (1) for each correct row

Total 5

2 a gaps are for undiscovered elements ✔

he predicted properties / new elementsmatched his predictions / new elementshad the properties he predicted ✔

2

b d and Zn / cadmium and zinc ✔

transition metals ✔

2 Both elements needed for one mark

Total 4

3 a i (s) shows it is a solid / (s) is the statesymbol / state symbol is a solid;

1 Must be linked to idea of state symbolIgnore ‘it shows it's a solid’ alone

Examiner's Comments

Most stated that ‘a solid is formed’. Thiswas not awarded a mark because it doesnot ‘use the equation to show’. Somecandidates did discuss the state symbol (s)linked to precipitate, but most failed to gaina mark.

ii silver nitrate + sodium chloride ? silverchloride + sodium nitrate

1 Examiner's Comments

About half the candidates correctly wrotethe word equation. Common incorrectanswers included using incorrect namessuch as ‘sodium chorine’ or ‘sodiumnitrogen oxide’.

b chlorine 1 Accept Cl2Do not allow ‘chloride’or ‘Cl’

Examiner's Comments

Most did not realise that silver chloridewould produce chlorine when it breaksdown to form silver. Oxygen and hydrogenwere commonly seen.

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Question Answer/Indicative content Marks Guidance

PhysicsAndMathsTutor.com

Total 3

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4 a gasliquidsolid (1)

greenorange / red-brown (1)

2

Accept green-yellow / yellow as colour ofchlorine.

Accept red or orange-brown, brown,orange.

Reject other colours.Ignore ‘dark’ ‘light’ ‘pale’ etc

Examiner's Comments

Many candidates gained no marks for thisquestion. The states and colours of thehalogens were not well known. Somethought that chlorine was orange. Manythought that iodine was a liquid.

b Box 2;

Box 3;

2 Examiner's Comments

Most gained at least one, and many gainedboth of these marks about the structure ofGroup 7 atoms and ions.

c two atoms / pair of atoms;

in each molecule / (covalently) bondedtogether;

2

Accept ‘which share a pair of electrons’ /‘joined together’Do not allow ionic bondDo not allow molecules/ions joinedtogetherIgnore double/tripleIgnore any examples / diagrams / formulae

Examiner's Comments

Most candidates did not know the meaningof the term ‘diatomic’; many gaveproperties of halogens such as reactivity orstate. Those who had an idea of themeaning often showed only partialunderstanding which was not enough togain credit such as ‘they go round in pairs’.Many confused molecules, elements andatoms, stating that ‘it contains twoelements’ or ‘it contains two molecules’.

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Total 6

5 a sodium hydroxide (1)

hydrogen (1)

2 Either order

Allow correct formula (NaOH and H2)

Examiner's Comments

About a third of candidates correctlycompleted the word equation for thereaction of sodium with water. Commonerrors were to incorrectly name either thealkali or the gas. Common incorrectanswers included sodium oxide, carbondioxide, oxygen or water being formed.

b add UI or pH paper / solution (1)

goes blue / purple / check the coloursagainst a reference idea / gives pH above7 (1)

OR

pH probe (1)

gives pH above 7 (1)

2 If no correct indicator is given, acceptLitmus (goes blue) for 1 mark only

Examiner's Comments

About a fifth of candidates did not correctlydescribe how to test pH. Most knew that‘an indicator’ is needed, but at this level ofdemand it is expected that they name anindicator fully, such as ‘Universal Indicator’.The use of a pH meter was less commonlystated.

c the two reactions have different ratesthe two reactions make different alkalis

1 Both needed

Examiner's Comments

This question demanded two correctanswers for a single mark. A commonincorrect choice was that ‘the reaction ofsodium takes less time than the reaction ofpotassium’. Just under half of thecandidates selected the two correctresponses.

Total 5

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6 a H2 + F2 ? 2HF

correct formulae (1)

correct equation balanced (1)

2

Do not allow h2 h2 H2 F2

Allow one mark for balancing if formulae ofhydrogen and / or fluorine contain minorerrors e.g. h2 h2 H2 F2

Examiner's Comments

Candidates found writing this equation verychallenging. Most did not know theformulae for hydrogen and fluorine. Themost common error was to representfluorine as 2F. As the balancing wasdependent on the correct formulae, this ledto most candidates failing to score.

b hydrogen iodide (1)

HI (1)

2 Do not allow hydrogen iodine

Accept 2HI

Examiner's Comments

About a third of candidates did not scoreany marks for deducing the name andformula of hydrogen iodide. Some who didscore wrote the correct formula but gavean incorrect name, such as ‘iodinehydroxide’ or ‘hydrogen iodine’.

c i become less reactive (down the group) 1Examiner's Comments

This question was well answered with mostcandidates correctly interpreting the trendin the table.

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ii less reactive than chlorine / reacts moreslowly than chlorine (1)

more reactive than iodine / reacts fasterthan iodine (1)

2 Chlorine or iodine must be mentioned.Ignore repeated observations from thetable.Ignore ‘because the reactivity decreasesdown the group’.

If 2 marks are not scored. Allow (1) for ideaof fitting between chlorine and iodine;

Examiner's Comments

Candidates need to take care whenanswering this type of question that theyaddress the task fully. Rather than discussthe trend in reactivity linked to the positionof bromine in the group, some merely re-quoted the observations in the table.

Total 7

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7 Level 3 (5–6 marks)Discusses properties of group 1 and linkswhy some properties mean that hydrogenfits and some properties mean that it doesnot fit. Quality of written communicationdoes not impede communication of thescience at this level.

Level 2 (3–4 marks)Discusses properties of group 1 and linkswhy a property of hydrogen fits and why aproperty does not fit. Quality of writtencommunication partially impedescommunication of the science at this level.

Level 1 (1–2 marks)Links some properties of hydrogen for why hydrogen fits OR does not fit group 1.Quality of written communication impedescommunication of the science at this level.

Level 0 (0 marks)Insufficient or irrelevant science. Answernot worthy of credit.

6 This question is targeted at grades up toA/A*

Relevant points include:Fay: Hydrogen fits Group 1 because…

it has same number / one electron in itsouter shellforms an ion with a single positivecharge / 1 + chargeforms a chloride with a similar formulato Group 1 chlorides (LiCl etc)very flammable / very reactivereacts with non-metals / group 7elements / halogens

Guy: Hydrogen does not fit / should bealone because…

it is a gasnon-metaldoes not react with waterforms compounds with metals (as wellas non-metals)(alone because) maximum electrons inouter shell is 2may gain an electron (to form an ion /give a full shell)forms covalent bonds

Properties about Group 1

contains solidscontains metalselements are flammable / reactivehas 1 electron in the outer shellidea that outer shell of common Group1elements holds up to 8 electronsform ions with single positive chargevery reactive with wateronly form compounds with non metalsreact with group 7 elements / halogensdo not react with other metals.

Use the L1, L2, L3 annotations in Scoris;do not use ticks.

Examiner's Comments

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This question was well answered and a fullrange of achievement was seen. Thecommonest score for the question was 4marks at Level 2. Candidates typicallyclassified the properties of hydrogen fromthe table into ‘fitting’ or ‘not fitting’ thestatements of Fay and Guy, but two broadtypes of error in the answers limited thecandidates’ scores. Firstly, some answersdid not fully link the properties of hydrogento the properties of group 1. The questionspecifically asked candidates to ‘use theirknowledge of group 1 elements’. Thereforesome answers were incomplete. Forexample, saying ‘hydrogen doesn't fit withgroup 1 because it is a gas’ is a lower levelanswer than ‘hydrogen doesn't fit withgroup 1 because it is a gas but group 1elements are all solids’. Secondly, someanswers gave very confusing accounts thatcompared the properties incorrectly, forexample stating that group 1 are all non-metals or that hydrogen must always gainelectrons to form an ion.

Total 6

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8 a (boiling point for) bromine / ?59; (1)

bromine is a liquid / must have a boilingpoint above 20°C / above roomtemperature / should be higher thanchlorine / boiling point should increase(down the group) / boiling point should behigher than the melting point (1)

2

ignore ‘it is too low’ aloneignore ‘it does not fit the pattern’

If chlorine is given as answer….For (1) mark max accept ‘chlorine (or ?35)because boiling points should increase(down the group)’ / ‘chlorine boiling pointshould be lower than bromine (or below-59)’ /AWignore ‘chlorine boiling point should belower’ alone, needs a comparison

Examiner's Comments

Most candidates gained both marks foridentifying bromine as having an incorrectboiling point, often linked to its liquid stateor to a correct comparison with its meltingpoint. Candidates, who suggested chlorineas the answer, were awarded a singlemark if they gave a correct reason linked tothe general trend in boiling points in thetable.

b Must give bromine as answer in (a)(+)59 / accept answers between 20 and150°C

1 Must be a numerical valueaccept a numerical range if both values fallbetween 20 and 150°C

Examiner's Comments

Just less than half of the candidates wenton to suggest a boiling point for brominethat was in the acceptable range (aboveroom temperature but well below that ofiodine).

c At2 1 do not accept at2 or AT2.do not accept At2. 2 must be smaller thanletters or subscripted.

Examiner's Comments

Most candidates correctly gave the formulafor astatine. Common errors includedpresenting astatine as atomic (At) or givingan incorrect symbol for the element (forexample As2).

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9 a Scientist 2 and scientist 5; (1)

Scientist 2 is evaluating / judging /analysing / criticising Mendeleev's work; (1)

Scientist 5 is checking / repeating anotherscientist's work / checking results / look forrepeatability; (1)

3

Ignore ‘reviewing’ (in the Q)Allow ‘give feedback’Ignore ‘talking about’ ‘discussing’ (notenough)

Allow ‘do the same experiment’ / ‘repeatthe experiment’

Examiner’s Comments

Most candidates identified 2 and 5correctly as the scientists involved in peerreview. In this question, marks were givenfor a straight ‘lift’ of information from thequestion stem. Saying that scientist 5 was‘repeating experiments’ was enough togain credit. For scientist 2, candidatesneeded to explain that his peer review wasbased on his criticism, evaluation orassessment of Mendeleev’s work.Candidates need to take care not to merelyrepeat the question. Answers which saidthat scientist 5 was ‘reviewing’ the work didnot gain credit as they closely repeated thequestion.

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b 2 fromMendeleev: left gaps for undiscoveredelements / made predictions aboutproperties;

Scientists: Idea of fitting / matching (in thegaps);

Idea that properties of new elements agreewith or support Mendeleev's predictions;

2

Ignore ‘goes in the gaps’ (in the Q)

Allow example of a property that matched


The majority of candidates scored at leastpartial credit here. However, in thisquestion, repeating the information in thestem or in the speech bubbles was notenough to show that candidatesunderstood how Mendeleev’s ideas weresupported. Some candidates repeatedinformation such as ‘they discovered newelements which go in the gaps’. Thestrongest answers made it clear that theproperties of the new elements matchedMendeleev’s predictions based on thegaps he deliberately left for elements heexpected to be later discovered.

Total 5

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10 a Toxic / corrosive / respiratory problems /irritates or damages lungs;

gas;

2 Allow poisonousIgnore harmful / hazardous / dangerous /can kill

Allow vapour

Examiner's Comments

??Most knew that chlorine is a toxic gas.Candidates need to make sure that whenasked about hazardous chemicals thatthey clearly identify the hazard. Those whosaid that chlorine is ‘harmful’ or ‘hazardous’or ‘will kill you’ did not score; candidatesneed to identify the nature of the hazard.‘Toxic’, ‘poisonous’ or ‘corrosive’ were allaccepted.

b I2 + 2KBr; (2)

For (1) markat least one formula correct I2 / KBr: ;

2 Allow BrK

Formulae and balancing fully correct = (2)

Examiner's Comments

Just under half of all candidates scoredpartial credit, usually for correctly giving theformula of either KBr or I2. Commonreasons for failing to score includedrepresenting iodine as 2I or potassiumbromide as K2Br2.

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c [Level 3]Links two reactions with reactivity andcorrect observations.Quality of written communication does notimpede communication of the science atthis level.

(5 – 6 marks)

[Level 2]Links a reaction to either the correctobservation or to reactivity.Quality of written communication partlyimpedes communication of the science atthis level.

(3 – 4 marks)

[Level 1]Makes a correct statement aboutobservations, reactions or reactivity.Quality of written communication impedescommunication of the science at this level.

(1 – 2 marks)

[Level 0]Insufficient or irrelevant science. Answernot worthy of credit.

(0 marks)

6 This question is targeted at grades up to A*

Indicative scientific points may include:Observations

KF (and KCl) no change / acceptyellow or green colour seen (due tochlorine)KBr orange / brown / yellow-brown /red-brown (ignore yellow or red alone)KI grey colour accept brown (ignoreviolet / purple)

Ignore states, look for colours aloneQWC is impeded if other incorrectobservations given e.g. precipitates orincorrect colours for elements (ignorebromine red or yellow and iodine violet orpurple)

Reactions

No reaction with KF (and KCl)Reaction occurs with KBr (may beimplied if observations are given)Reaction occurs with KI (may beimplied if observations are given)

Allow Level 1 only for no reaction betweenchlorine and potassium chloride

Reactivity

Cl2 less reactive than F2 / cannotdisplace F2Cl2 more reactive than Br2 / candisplace Br2Cl2 more reactive than I2 / can displaceI2Reactivity gets less down the group

QWC is impeded if ‘chlorine’ is confusedwith ‘chloride’ etc.


Examiner's Comments

The question asked for a statement and an

© OCR 2019. 38 of 45



explanation of what would be seen whenchlorine was passed over solutions ofpotassium halides. In this type of question,candidates need to pause to think aboutwhat they need to include in their answer;in this case, a description of observationslinked to an explanation. Many answers didnot include observations; some gaveobservations but did not include anexplanation for the changes. Theseanswers were limited to the lower levels.Answers at level 3 both described thecorrect colour changes and explainedthese in terms of the reactivity of theelements compared to chlorine. Somecandidates thought that all combinationswould give a reaction, including chlorinewith potassium fluoride. In answers whichdescribed observations, candidates knewsome or all of the colours of the halogens.In this case incorrect statements of statee.g. bromine gas or liquid, were notpenalised but were ignored. Similarly,correct colours for elements in states otherthan those in the question (for examplepurple linked to iodine) were also ignored.

Total 10

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11 a group 1 more reactive down the group /group 1 react faster down the group; (1)

group 2 more reactive down the group /group 2 react faster down the group; (1)

group 1 more reactive than group 2 / group1 react faster than group 2; (1)

3 Accept for 2 marks ‘In BOTH groups thereactivity increases going down the group’

Ignore comparison between individualmetals alone.

Ignore answers which only mention timetaken

Examiner's Comments

??Candidates needed to use theinformation in the table to makeconclusions about reactivity. Manycandidates interpreted the information welland presented their conclusions clearly.Most gained some marks. The mostcommon reason that some candidates didnot score was that they repeated theinformation in the table, for example saying‘the times get shorter’ rather than interpretthe information to make a conclusion aboutreactivity (‘the elements become morereactive down the group’). Somecandidates gained partial credit by spottingsome, but not all of the three trends in thedata.

b TFFF 2 All correct = (2)2 or 3 correct = (1)1 correct = 0

Examiner's Comments

??Most gained a single mark. The secondbox, which stated that ‘Each reactionmakes a different metal oxide’ proved mostchallenging, with many candidatesclassifying this statement as correct, eventhough the question was about elementsreacting with water.

Total 5

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12[Level 3]Identifies trends in both radius and energy AND links electron shells to one of thetrends.Quality of written communication does notimpede communication of the science atthis level.

(5 – 6 marks)

[Level 2]Identifies both trends (atomic radii andenergy needed to remove an electron) AND describes the electron arrangement intwo or more atoms.ORIdentifies one trend and gives a level 3 linkbetween electron shells and the trend.Quality of written communication partlyimpedes communication of the science atthis level.

(3 – 4 marks)

[Level 1]Describes at least one trend in the dataOR describes the electron arrangement intwo or more atoms.Quality of written communication impedescommunication of the science at this level.

(1 – 2 marks)

[Level 0]Insufficient or irrelevant science. Answernot worthy of credit.

(0 marks)

6 This question is targeted at grades up to A*

Indicative scientific points may include:

Links electron shells to trends in radius /energy (level 3)

more (electron) shells causes a largeratomic radius / idea that the atom islarger if it has more shellsstatement of idea that outer shellelectrons are further away fromnucleus in bigger atoms.More electron shells need less energyto remove electron / easier to removean electronMore electron shells lead to moreshielding.Further from nucleus, less energyneeded to remove electron / easier toremove an electron

Describes electron arrangement (level 2and 1)

Li 2,1. Na 2,8,1 K 2,8,8,1 / drawscorrect diagramsidentifies the number of electron shellsin at least two atomsidentifies a trend in electron shells /down the group there are more shells /atoms with more electrons have moreelectron shells.

Describes the trends in the data (all levels)

atomic radius increases with increasingelectron number or down the groupenergy needed to remove electrondecreases with increasing electronnumber or down the grouplarger radius, less energy needed toremove electron or larger radius, easierto remove an electron


Examiner's Comments

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This question relied on the interpretation ofdata. Candidates processed the data well,showing that they are skilled atmanipulating unfamiliar data.

About a quarter of candidates gained alevel 1 or zero marks. This was usuallybecause they did not engage fully with thequestion. To gain a level 2, the answerneeded to discuss the data in the contextof electron shells. Many candidatesreferred only to numbers of electrons(which were given in the table) rather thandiscussing electron shells (which is whatthe question asked about).

However, those who did discuss thearrangement of electrons in shells showedvery good understanding of concepts suchas the effect of increasing distance of outerelectrons from the nucleus. Some veryhigh level responses were seen. Well overa third of candidates gained a level 3.

Some candidates showed poorcommunication skills by confusingelectrons with atoms in their answers.

Total 6

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13 a Bromine/Br2 identified ✓

displaced (by the chlorine) / chlorine ismore reactive than bromine ✓

Cl2 + 2Br- → Br2 + 2Cl- ✓

3 (AO 3 ×1.1)

ALLOW from equation

IGNORE ‘replace’DO NOT ALLOW ‘chloride displacesbromideALLOW ‘chlorine displaces bromide’ forMP2

IGNORE K+ ions


Most candidates knew that chlorine is morereactive than bromine and many went on toexplain that this means that bromine isdisplaced, causing the brown colour. Theionic equation was the main discriminatorymark, with only the higher abilitycandidates giving a correct equation.Common errors were incorrect formula(such as 2Br) or attempting to write fullequations which included the potassiumions.

Exemplar 1

This candidate knows that chlorine is morereactive than bromine [1] and that bromineis displaced (giving an orange-browncolour) [1]. Notice, however, that the ionicequation contains potassium and hasseveral incorrect formulae, includingincorrect formulae for the two halogensinvolved in the reaction. This was a typicalcommon error.

b Astatine reacts with sodium to form NaAt ✓

Astatine is less reactive than iodine ✓

1 (AO2.1)

Total 4

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14 a fluorineprotons: 9neutrons : 10group: 7 / 17

3 (AO 3 ×2.1)

All 4 correct = ✓ ✓ ✓3 correct = ✓ ✓1 or 2 correct = ✓


This question was well answered. Almostall candidates correctly identified both thegroup and the element. Some put thenumbers of protons and neutrons in thewrong order.

b i - 1 ✓

it has gained (an) electron ✓

2 (AO2.1)

(AO 1.1)

ALLOW ‘-‘ IGNORE ‘negative’

ALLOW M2 for idea of gaining electrons,even if M1 is not awarded.ALLOW ‘has (one) more electron thanprotons’


Most knew that the atom had gained anelectron. When giving a charge on an ion,‘negative’ is not enough, a negative ioncould have a range of charges. Bestanswered stated clearly that the charge is‘–1’.

ii the atoms both have 7 electrons in the outer shell / both atoms have the samenumber of electrons in the outer shell /both need one electron to give a full outershell ✓

1 (AO1.1)

Total 6

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15 a 4 ✓ 1 (AO2.1)

b they were not yet discovered / he didn’tknow about them ✓

1 (AO2.1)


Both of these part questions were very wellanswered. Candidates interpreted theinformation well and applied it to thecontext.

c In any order: Cu Zn Cr ✓✓ 2 (AO 2×2.1)

ALLOW namesIGNORE Fe Co NiDO NOT ALLOW any other additionalelements (apply list principle)

All three correct = 2 marksTwo or one correct = 1 mark


Most earned at least one mark foridentifying one transition metal correctly.Others either included non-transitionmetals in the list or used their periodictable to find examples of transition metalsthat were not from Mendeleev’s table. It isimportant that candidates read thequestion carefully to ensure that they followthe instructions.

Total 4

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1(a). group 1 and group 7 of the periodic table both

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